Dientamoeba fragilis (D. fragilis) is one of the most common parasites affecting animals including humans. It is thought to be spread via pinworms acquired by the faecal/oral route and to reside in the gastrointestinal tract of the host, clinically causing such symptoms as abdominal discomfort, loose motions, bloating, diarrhoea, at times nausea, pruritus ani, malaise and other non-specific symptoms. It is perhaps one of the most common parasites residing in the gastrointestinal tract of individuals in the western world and yet few physicians are aware of its presence and its contribution to disease, chiefly due to the fact that it is not diagnosed frequently.
Dientamoeba fragilis is notoriously difficult to diagnose unless suitable fixatives and permanent staining methods are employed and adequately trained personnel are available (Windsor and Johnson 1999—Windsor J J, Johnson E H. Dientamoeba fragilis: the unflagellated human flagellate. A review. Br J Biomed Sci 1999; 56:293-306). Culture methods have been shown to be more sensitive than microscopy at times (Ockert 1990, Sawangjaroen 1993—Ockert G., Symptomatology, pathology, epidemiology and diagnosis of Dientamoeba fragilis: In: Honiberg B M, ed., Trichomonads parasitic in humans. New York; Springer 1990; 394-410), however these culture methods are not currently used in diagnostic laboratories because of their complexity.
If the methodology could be simplified, culture would be more easy to perform and would have the added advantage that the isolates can be lysed and typed, thus aiding future epidemiological studies on top of simple diagnostic studies. D. fragilis does not have a resistant cyst stage and consequently cannot survive outside the human host for longer than 12 hours (Sawangjaroen 1993—Sawangjaroen N, Luke R, Provic P., Diagnosis by faecal culture of Dientamoeba fragilis in Australian patients with diarrhoea. Trans Roy Soc Trop Med Hyg 1993; 87:163-5). In order for the culture method to be successful, the culture medium needs to be simple and needs to be one that will support the growth of D. fragilis and other parasites, e.g. Blastocystis hominis. Furthermore, the medium needs to have the features of long shelf life and transportability. In addition, the detection of the growing parasites needs to be carried out easily by technicians with minimal training. Previous methods have included specific stains, e.g., trichome and iron-haematoxylin, and more recently Riordan (U.S. Pat. No. 5,334,509) has suggested an acridine orange or acridine yellow stain for more specifically detecting D. fragilis. However, this method lacks specificity as it merely stains up RNA/DNA and therefore stains numerous parasites, including non-pathogenic ones. Using this method D. fragilis is at times indistinguishable microscopically from such parasites, and so the diagnosis again depends on the availability of highly trained microscopists to diagnose D. fragilis. 
It would also be desirable to simplify the culture medium so that it can be used by an unskilled technician.